Hi
When I went on the sugar quit plan I asked my GP to monitor my bloods. My cholesterol dropped from 5.4 to 4.3 in 3 months.
I eat butter but I still cook with olive oil. I think the research which is showing that the irritation high blood sugar levels cause to blood vessel linings contributes more to cholesterol build up is feasible. I have not read any other books by David.
Of course, it is never one thing. If you want to be healthy, you still need to exercise gently and eat moderate amounts. You can still get fat on a low-fructose diet if you are stuffing your face with low-sugar carrot cake (delicious recipe on this website, BTW) and eating past the "i am full" feeling.
If you are worried about your cholesterol, I would talk to your GP about it. Mine was very receptive, and since I have lost 15kg over a year with no difficulty, the actual weight loss has been a major factor in reducing my blood pressure too.
I hope you are sticking with it. Christmas is a difficult time to go low-fructose, but this was my second Christmas, and I ate very well - lots of yummy food - but no sugar, and no xmas weight gain either.
Best of luck,
Heidi